Articles
Performance of dwarfing and semi-dwarfing plum rootstocks on three European plum scion cultivars in a Nordic climate
Article number
1260_28
Pages
181 – 186
Language
English
Abstract
For plum production to be economically viable, dwarfing rootstocks are essential for establishing high-density orchards, which ensure easier management, lower production costs, and earlier yields.
Performance of the semi-dwarfing plum rootstocks Wavit, Ute (both clones of Prunus domestica), and the dwarfing VVA-1 (Krymsk®1) was compared against the industry standard, St.
Julien A. Onto these rootstocks, scion cultivars Excalibur, Reeves, and Valor were grafted and assessed in a replicated field trial in western Norway at 60° North.
Trees were planted in spring 2006 and the
VVA-1 rootstock in May 2007. Plants were all one-year-old whips, spaced 2.0×4.0 m apart and trained to a central leader as free spindles.
Tree vigour, yield, fruit size, fruit quality, and yield efficiency were evaluated for eight subsequent years.
Tree size was significantly influenced by the rootstock after eight years of growth. VVA-1 produced the smallest trees, about half the tree size of St.
Julien A as measured by trunk cross-sectional area. Wavit and Ute were similar in size to St.
Julien A. All plum trees came into production slowly.
On average the cultivars Excalibur and Reeves were harvested in mid-September and Valor two weeks later.
During the period 2011-2014, when trees were fully mature, Reeves and Valor grafted on the three semi-dwarfing rootstocks resulted in the highest yields tree-1. VVA-1 resulted in significantly lower yields for Valor. Excalibur was the only cultivar in which VVA-1 significantly increased yield efficiency.
Accumulated yield from 2011-2015 on VVA-1 was 0.52 kg cm-2 TCSA, 2.3 times more than on St Julien A. Fruit weight in Excalibur and Reeves was on average 57 and 62 g, respectively, and not affected by the different rootstocks. Valor on VVA-1 showed a 10 g reduction in fruit weight compared to 59 g fruit weight on the other rootstocks.
Fruit soluble solids were on average around 13 °Brix for Excalibur and Reeves and 16 °Brix for Valor and did not differ significantly between trees on the different rootstocks tested.
In conclusion, St.
Julien A was the most reliable semi-vigorous rootstock and resulted in the highest accumulated yields over the first eight years after planting and with favourable effects on fruit quality of all European plum cultivars evaluated. VVA-1 resulted in trees of low vigour which, especially with Excalibur, were more precocious and had higher yield efficiencies than all other rootstock scion combinations.
If this rootstock is to be used it should be planted at a higher density per area than the semi-dwarfing rootstocks and on fertile soil with fertigation provided.
Performance of the semi-dwarfing plum rootstocks Wavit, Ute (both clones of Prunus domestica), and the dwarfing VVA-1 (Krymsk®1) was compared against the industry standard, St.
Julien A. Onto these rootstocks, scion cultivars Excalibur, Reeves, and Valor were grafted and assessed in a replicated field trial in western Norway at 60° North.
Trees were planted in spring 2006 and the
VVA-1 rootstock in May 2007. Plants were all one-year-old whips, spaced 2.0×4.0 m apart and trained to a central leader as free spindles.
Tree vigour, yield, fruit size, fruit quality, and yield efficiency were evaluated for eight subsequent years.
Tree size was significantly influenced by the rootstock after eight years of growth. VVA-1 produced the smallest trees, about half the tree size of St.
Julien A as measured by trunk cross-sectional area. Wavit and Ute were similar in size to St.
Julien A. All plum trees came into production slowly.
On average the cultivars Excalibur and Reeves were harvested in mid-September and Valor two weeks later.
During the period 2011-2014, when trees were fully mature, Reeves and Valor grafted on the three semi-dwarfing rootstocks resulted in the highest yields tree-1. VVA-1 resulted in significantly lower yields for Valor. Excalibur was the only cultivar in which VVA-1 significantly increased yield efficiency.
Accumulated yield from 2011-2015 on VVA-1 was 0.52 kg cm-2 TCSA, 2.3 times more than on St Julien A. Fruit weight in Excalibur and Reeves was on average 57 and 62 g, respectively, and not affected by the different rootstocks. Valor on VVA-1 showed a 10 g reduction in fruit weight compared to 59 g fruit weight on the other rootstocks.
Fruit soluble solids were on average around 13 °Brix for Excalibur and Reeves and 16 °Brix for Valor and did not differ significantly between trees on the different rootstocks tested.
In conclusion, St.
Julien A was the most reliable semi-vigorous rootstock and resulted in the highest accumulated yields over the first eight years after planting and with favourable effects on fruit quality of all European plum cultivars evaluated. VVA-1 resulted in trees of low vigour which, especially with Excalibur, were more precocious and had higher yield efficiencies than all other rootstock scion combinations.
If this rootstock is to be used it should be planted at a higher density per area than the semi-dwarfing rootstocks and on fertile soil with fertigation provided.
Authors
M. Meland, O. Frøynes, F. Maas
Keywords
precocity, productivity, compatibility, total soluble solids, titratable acidity
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